Windows are drafty etc and heating through out the house is very Inconsistent. 

Credit Union #1: This has the longest maturity, so there's an element of "fire and forget" here too.

There's still the elements of 1) there's not a lot of 2-4 unit properties in comparison to SFH and 2) the average family doesn't want to purchase a 2-4 unit property. 

Only these type of requests (water leak and no heat are urgent) and then you should text/call (your preference).

So I analyse each property individually, looking at major features like roof, heating, cooling, hot water, anything likely to break down really. 

Or is the landlord always responsible for the water bill and heat?

The heat is problematic.

Last week this tenant casually informed me by text that he had hired a heating guy to service the furnace of the building that is in his half of the duplex.

Seek out neighborhoods where demand is steady or increasing, and take into account elements like conveniences, safety, and the closeness to public transit.Pick a home that fits in with your long-term objectives.

What's important is secondary security locks, AC/Heat for all living sq footage, all working outlets, damp rated bulbs in bathrooms, working appliances, fire extinguishers, we do 1 year worth of monthly air filters, which cost way less than ceiling fans, working fire alarms, etc.Best wishes, good luck.